E-Cards are becoming prominent in games...and Pinball R/S is no different. The 3 E-Cards known are part of a promotion when you buy Pinball R/S from the Japanese Pokémon Center. There may be more and it is not known if these will come with the US game.
However these cards functions are known and are below...however the translation may be slightly inaccurate

DX Mode Card:

When this card is scanned in, the amount of times that Pikachu or Pichu saves your ball is increased!

This card was a Promo card given with release of Pinball R/S in Japan

Capture Difficulty UP Card:

With this card scanned in, the amount of time that Latios and Latias save your ball is increased

This card was a Promo card given with release of Pinball R/S in Japan

Area Card:

With this card scanned in, you can get moved to the place of Jirachi More times aswell as Bonuses being more frequent

This card was a Promo card given with release of Pinball R/S in Japan

Extra Pokémon Get:

With this card scanned in, you're encounter chances of Chikorita, Cyndaquil, Totodile and Aerodactyl are increased so you are likely to get them more often

This card was given away at certain e-reader+ trial stands in Japan

Many of you have been questioning how these e cards work so here is the explanation of how they are activated.. Step by step;

First, Enter the Pokédex Mode on the Main Menu

Press Start and begin transfer as if you were trading records. At this point scan the card into the e reader and follow on screen instructions

Voila, It's Done. Now the added programming is in the game...here the Extra Pokémon are blanked out until you capture them with increased chances